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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower Improvement Research » Research » Publications at this Location » Publication #435658
Research Project: Sunflower Yield, Crop Quality, and Interactions with Biotic and Abiotic Stressors

Location: Sunflower Improvement Research

Title: Untargeted metabolomic profiling of cell-free culture filtrates of D. gulyae and D. helianthi causing Phomopsis stem canker of sunflower

Author
item MOHAN, KARTHIKA - North Dakota State University
item Underwood, William
item MARKELL, SAMUEL - North Dakota State University
item MCCAGHEY, MEGAN - University Of Minnesota
item MATHEW, FEBINA - North Dakota State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Phomopsis stem canker of sunflower (Helianthus annuus L.), caused by Diaporthe gulyae and D. helianthi, can reduce yield by up to 40%. Although the phytotoxic metabolites, phomozin and 4,6-dihydroxymellein, have been identified from D. helianthi, it is not known whether U.S. isolates of D. gulyae and D. helianthi produce these same compounds or synthesize additional secondary metabolites. This study compared the metabolomic profiles of strongly and weakly aggressive isolates of both D. gulyae and D. helianthi. Aggressiveness was assessed by measuring the necrotic area induced on a susceptible sunflower cultivar following leaf infiltration with cell-free culture filtrates. The isolates were cultured in potato dextrose broth (PDB) for 21 days in the dark, after which the cultures were filtered, centrifuged, and analyzed using untargeted metabolomics. Several putative phytotoxic metabolites were significantly upregulated in the culture filtrates of aggressive isolates compared to non-inoculated PDB controls. For D. gulyae, 3-nitropropionic acid (FC=10.6; P=0.013), previously associated with necrosis on sunflower, and fumonisin B2 (FC=9.4; P=0.001), a mycotoxin generally produced by Fusarium species, were detected. In D. helianthi, gliotoxin (FC=1.1; P=0.017), known to induce host cell death, was identified. Notably, phomozin and 4,6-dihydroxymellein were not detected. These results offer new insights into the secondary metabolites that may contribute to the severity of Phomopsis stem canker in sunflower.